One of the initial steps in forming cylindrical containers such as cans for carbonated beverages is forming a cup. A typical cup includes a circular base connected to a cylindrical sidewall. The cup is typically shorter and wider than a finished container. As such, the cups are typically subjected to a variety of additional processes that further form the cup into a finished container.
Container manufacturing lines operate at high speeds to produce large quantities of containers. Throughout these manufacturing lines, the container elements are transported from one work station to another work station where different forming processes are performed. One of the problems encountered in designing the manufacturing lines is that the container elements often become deformed when being transported from station to station. As the speed of the lines increases, the number of container elements that become deformed increases. This problem is aggravated by the constantly increasing economic pressures to reduce the gauge of the material used to form the containers. The deformations are caused by the collisions between the container elements and contact between the container elements and the machinery.
One deformation problem occurs after the initial step of forming a cup from a flat blank of material has occurred. The cups are generally intended to have circular bottoms with straight, cylindrical sidewalls. Later processes that further form these cups include tooling designed to operate on substantially cylindrical cups. After the cups are initially formed, however, various forces can cause the cups to warp. If a cup is sufficiently warped, the container eventually formed from it must be discarded as waste. Additionally, tooling damage and/or jamming can occur. It has therefore become desirable to form a cup that is more resistant to warping and deformation.